1. Field of the Invention
The present general inventive concept relates to an audio reproduction apparatus and method, and more particularly, to an audio reproduction apparatus and method, in which an audio volume can be automatically controlled based on audio energy and human auditory characteristics.
2. Description of the Related Art
Research on noise-induced hearing loss shows that hearing may be damaged by long-period exposure to noise of a higher level than a predetermined level. For this reason, various international industrial accident-related organizations establish noise exposure control regulations and use them as industrial accident-related standards.
As the number of users of portable devices and earphones (or headphones) increases, a more number of users complain of serious levels of hearing damage.
In this context, audio volume control apparatuses for protecting hearing have been developed.
U.S. 2003/0002688 A1, published on Jan. 2, 2003 and entitled “Volume Regulating and Monitoring System,” discloses a conventional technique related to a conventional audio volume control apparatus.
In the conventional audio volume control apparatus, an input audio signal is converted into an electric signal, the electric signal is compared with a threshold, an alarm signal is generated every time the electric signal exceeds the threshold, and then the adjusted audio signal is output.
According to research on noise-induced hearing loss, it is known that hearing loss is proportional to the total energy of noise, i.e., (audio volume×time). In other words, according to noise exposure standards, hearing loss is induced by exposure to 85 dB noise for 8 hours, 88 dB noise for 4 hours, 91 dB noise for 2 hours, and 97 dB noise for 30 minutes.
According to the conventional technique related to the volume control apparatus, a threshold for preventing hearing loss is set by referring to only audio volume.
As a result, even if the audio signal is adjusted to below the threshold, hearing loss may also be induced by long-time exposure to the audio signal.
Moreover, the conventional volume control apparatus does not consider a fact that the sensitivity of ears varies with audio frequency components. Since the human ears are generally insensitive to low-frequency sound, they may feel intermediate/high-frequency sound louder when they concentrate on low-frequency sound.